1. Field of the Invention
The present invention relates to an image forming apparatus which can print on various types of paper, and more particularly, to an apparatus and method for identifying paper cassettes by using a simple structure.
2. Description of the Related Art
An image forming apparatus such as a printer includes a plurality of paper cassettes for supporting paper. Paper which corresponds to a paper size selected by a user is extracted from the plurality of paper cassettes, and a printing operation is performed.
In the conventional image forming apparatus, two methods for identifying a plurality of paper cassettes have been used. In the first method, an identification symbol is assigned to each of the paper cassettes, and a main controller identifies the identification symbols included in the apparatus, and the main controller and the paper cassettes are independently connected to serial buses, respectively. Thus, the number of serial buses is the same as the number of paper cassettes. Therefore, when a paper cassette which corresponds to a specific identification symbol is detected by the main controller, a signal is transmitted to a unit in the apparatus via a serial bus connected to the corresponding paper cassette, and paper of a corresponding size is used from the detected paper cassette.
In the second method, a main controller and paper cassettes are connected to one serial bus, and each of the paper cassettes comprises a switch so that a user can manually set identification symbols.
In the first method, the number of connection lines of the serial buses should be the same as the number of paper cassettes, and therefore, it may be difficult to manufacture an image forming apparatus and manufacturing costs may increase.
In the second method, the user manually sets the identification symbols one by one by operating the switch of each paper cassette. Also, when the user mistakenly fails to operate the switch, due to wrong setting of the identification symbols, errors may occur while the image forming apparatus is operating.